Calibration and Validation of SWAT Model for a Himalayan Snowfed River Basin Combining IMD and MERRA-2 Sourced Climatic Input

The Himalayan basins experience substantial snowfall during the winter season, and this accumulated snow is major cradle for breeding streamflow during the spring. In this investigation, gridded climate inputs temperature, speed of wind and solar radiation was acquired from the (MERRA-2) was employed. A semi distributed hydrological model was established on behalf of the snowfed Bhagirathi River basin, integrating precipitation data from the IMD and other climate inputs from MERRA-2, utilizing the SWAT (Soil and Water Assessment Tool) model within the interface of ArcMap. The model underwent calibration (2005–2009) and validation (2012–2013) using recorded discharge data at Uttarkashi. The model demonstrated good performance in simulating streamflow, with efficacy measures such as Nash–Sutcliffe efficiency (NS) along with coefficient of determination (R) reaching 0.83 and 0.87, respectively during calibration. The values for performance statistics are 0.83 (NSE) and 0.87 (R) for validation period. The findings indicate that the incorporation of MERRA-2 data into the SWAT model for Himalayan basins can be proficiently executed, highlighting the dependability and promising utility of this data pool in hydrological modeling.